Trejo has appeared in movies such as Spy Kids, Spy Kids 2: Island of Lost Dreams, Spy Kids 3-D: Game Over, Spy Kids: All the Time in the World in 4D , Delta Farce, Desperado, Valley of Angels, Fanboys, The Muppets, Top Cat: The Movie and Muppets Most Wanted. He got his first lead role in Robert Rodriguez's action film Machete and Machete Kills.

He also appeared in TV shows such as King of the Hill, Desperate Housewives, Burn Notice, Brooklyn South, NCIS: Los Angeles, The Young and the Restless, Young Justice, Stargate: Atlantis, Modern Family, Bones, Phineas and Ferb, Sons of Anarchy, Reasonable Doubts, Maron, Alias, The Spectacular Spider-Man, George Lopez, Breaking Bad, The Cleveland Show, NYPD Blue, Franklin & Bash, Blood Ties, Walker, Texas Ranger, The High Fructose Adventures of Annoying Orange, The District, Jake and the Fatman, Heist, Tim and Eric Awesome Show, Great Job! and Grounded for Life.

In video games, besides his role as Robina in the GTA series, he's been featured in Def Jam: Fight for NY (where also his likeness was added as a fighter), Fallout: New Vegas, and Call of Duty: Black Ops.